mirror of
https://github.com/letic/terraform-provider-google.git
synced 2024-09-07 09:36:44 +00:00
392 lines
9.6 KiB
Go
392 lines
9.6 KiB
Go
package dag
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"io"
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"sort"
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)
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// Graph is used to represent a dependency graph.
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type Graph struct {
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vertices *Set
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edges *Set
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downEdges map[interface{}]*Set
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upEdges map[interface{}]*Set
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// JSON encoder for recording debug information
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debug *encoder
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}
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// Subgrapher allows a Vertex to be a Graph itself, by returning a Grapher.
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type Subgrapher interface {
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Subgraph() Grapher
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}
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// A Grapher is any type that returns a Grapher, mainly used to identify
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// dag.Graph and dag.AcyclicGraph. In the case of Graph and AcyclicGraph, they
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// return themselves.
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type Grapher interface {
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DirectedGraph() Grapher
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}
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// Vertex of the graph.
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type Vertex interface{}
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// NamedVertex is an optional interface that can be implemented by Vertex
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// to give it a human-friendly name that is used for outputting the graph.
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type NamedVertex interface {
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Vertex
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Name() string
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}
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func (g *Graph) DirectedGraph() Grapher {
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return g
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}
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// Vertices returns the list of all the vertices in the graph.
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func (g *Graph) Vertices() []Vertex {
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list := g.vertices.List()
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result := make([]Vertex, len(list))
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for i, v := range list {
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result[i] = v.(Vertex)
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}
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return result
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}
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// Edges returns the list of all the edges in the graph.
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func (g *Graph) Edges() []Edge {
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list := g.edges.List()
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result := make([]Edge, len(list))
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for i, v := range list {
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result[i] = v.(Edge)
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}
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return result
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}
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// EdgesFrom returns the list of edges from the given source.
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func (g *Graph) EdgesFrom(v Vertex) []Edge {
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var result []Edge
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from := hashcode(v)
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for _, e := range g.Edges() {
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if hashcode(e.Source()) == from {
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result = append(result, e)
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}
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}
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return result
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}
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// EdgesTo returns the list of edges to the given target.
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func (g *Graph) EdgesTo(v Vertex) []Edge {
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var result []Edge
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search := hashcode(v)
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for _, e := range g.Edges() {
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if hashcode(e.Target()) == search {
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result = append(result, e)
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}
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}
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return result
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}
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// HasVertex checks if the given Vertex is present in the graph.
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func (g *Graph) HasVertex(v Vertex) bool {
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return g.vertices.Include(v)
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}
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// HasEdge checks if the given Edge is present in the graph.
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func (g *Graph) HasEdge(e Edge) bool {
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return g.edges.Include(e)
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}
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// Add adds a vertex to the graph. This is safe to call multiple time with
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// the same Vertex.
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func (g *Graph) Add(v Vertex) Vertex {
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g.init()
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g.vertices.Add(v)
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g.debug.Add(v)
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return v
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}
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// Remove removes a vertex from the graph. This will also remove any
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// edges with this vertex as a source or target.
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func (g *Graph) Remove(v Vertex) Vertex {
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// Delete the vertex itself
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g.vertices.Delete(v)
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g.debug.Remove(v)
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// Delete the edges to non-existent things
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for _, target := range g.DownEdges(v).List() {
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g.RemoveEdge(BasicEdge(v, target))
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}
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for _, source := range g.UpEdges(v).List() {
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g.RemoveEdge(BasicEdge(source, v))
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}
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return nil
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}
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// Replace replaces the original Vertex with replacement. If the original
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// does not exist within the graph, then false is returned. Otherwise, true
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// is returned.
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func (g *Graph) Replace(original, replacement Vertex) bool {
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// If we don't have the original, we can't do anything
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if !g.vertices.Include(original) {
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return false
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}
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defer g.debug.BeginOperation("Replace", "").End("")
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// If they're the same, then don't do anything
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if original == replacement {
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return true
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}
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// Add our new vertex, then copy all the edges
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g.Add(replacement)
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for _, target := range g.DownEdges(original).List() {
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g.Connect(BasicEdge(replacement, target))
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}
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for _, source := range g.UpEdges(original).List() {
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g.Connect(BasicEdge(source, replacement))
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}
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// Remove our old vertex, which will also remove all the edges
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g.Remove(original)
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return true
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}
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// RemoveEdge removes an edge from the graph.
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func (g *Graph) RemoveEdge(edge Edge) {
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g.init()
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g.debug.RemoveEdge(edge)
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// Delete the edge from the set
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g.edges.Delete(edge)
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// Delete the up/down edges
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if s, ok := g.downEdges[hashcode(edge.Source())]; ok {
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s.Delete(edge.Target())
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}
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if s, ok := g.upEdges[hashcode(edge.Target())]; ok {
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s.Delete(edge.Source())
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}
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}
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// DownEdges returns the outward edges from the source Vertex v.
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func (g *Graph) DownEdges(v Vertex) *Set {
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g.init()
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return g.downEdges[hashcode(v)]
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}
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// UpEdges returns the inward edges to the destination Vertex v.
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func (g *Graph) UpEdges(v Vertex) *Set {
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g.init()
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return g.upEdges[hashcode(v)]
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}
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// Connect adds an edge with the given source and target. This is safe to
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// call multiple times with the same value. Note that the same value is
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// verified through pointer equality of the vertices, not through the
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// value of the edge itself.
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func (g *Graph) Connect(edge Edge) {
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g.init()
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g.debug.Connect(edge)
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source := edge.Source()
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target := edge.Target()
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sourceCode := hashcode(source)
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targetCode := hashcode(target)
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// Do we have this already? If so, don't add it again.
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if s, ok := g.downEdges[sourceCode]; ok && s.Include(target) {
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return
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}
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// Add the edge to the set
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g.edges.Add(edge)
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// Add the down edge
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s, ok := g.downEdges[sourceCode]
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if !ok {
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s = new(Set)
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g.downEdges[sourceCode] = s
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}
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s.Add(target)
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// Add the up edge
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s, ok = g.upEdges[targetCode]
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if !ok {
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s = new(Set)
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g.upEdges[targetCode] = s
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}
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s.Add(source)
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}
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// String outputs some human-friendly output for the graph structure.
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func (g *Graph) StringWithNodeTypes() string {
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var buf bytes.Buffer
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// Build the list of node names and a mapping so that we can more
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// easily alphabetize the output to remain deterministic.
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vertices := g.Vertices()
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names := make([]string, 0, len(vertices))
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mapping := make(map[string]Vertex, len(vertices))
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for _, v := range vertices {
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name := VertexName(v)
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names = append(names, name)
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mapping[name] = v
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}
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sort.Strings(names)
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// Write each node in order...
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for _, name := range names {
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v := mapping[name]
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targets := g.downEdges[hashcode(v)]
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buf.WriteString(fmt.Sprintf("%s - %T\n", name, v))
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// Alphabetize dependencies
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deps := make([]string, 0, targets.Len())
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targetNodes := make(map[string]Vertex)
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for _, target := range targets.List() {
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dep := VertexName(target)
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deps = append(deps, dep)
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targetNodes[dep] = target
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}
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sort.Strings(deps)
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// Write dependencies
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for _, d := range deps {
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buf.WriteString(fmt.Sprintf(" %s - %T\n", d, targetNodes[d]))
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}
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}
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return buf.String()
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}
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// String outputs some human-friendly output for the graph structure.
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func (g *Graph) String() string {
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var buf bytes.Buffer
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// Build the list of node names and a mapping so that we can more
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// easily alphabetize the output to remain deterministic.
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vertices := g.Vertices()
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names := make([]string, 0, len(vertices))
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mapping := make(map[string]Vertex, len(vertices))
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for _, v := range vertices {
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name := VertexName(v)
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names = append(names, name)
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mapping[name] = v
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}
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sort.Strings(names)
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// Write each node in order...
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for _, name := range names {
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v := mapping[name]
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targets := g.downEdges[hashcode(v)]
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buf.WriteString(fmt.Sprintf("%s\n", name))
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// Alphabetize dependencies
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deps := make([]string, 0, targets.Len())
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for _, target := range targets.List() {
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deps = append(deps, VertexName(target))
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}
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sort.Strings(deps)
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// Write dependencies
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for _, d := range deps {
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buf.WriteString(fmt.Sprintf(" %s\n", d))
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}
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}
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return buf.String()
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}
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func (g *Graph) init() {
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if g.vertices == nil {
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g.vertices = new(Set)
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}
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if g.edges == nil {
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g.edges = new(Set)
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}
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if g.downEdges == nil {
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g.downEdges = make(map[interface{}]*Set)
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}
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if g.upEdges == nil {
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g.upEdges = make(map[interface{}]*Set)
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}
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}
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// Dot returns a dot-formatted representation of the Graph.
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func (g *Graph) Dot(opts *DotOpts) []byte {
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return newMarshalGraph("", g).Dot(opts)
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}
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// MarshalJSON returns a JSON representation of the entire Graph.
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func (g *Graph) MarshalJSON() ([]byte, error) {
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dg := newMarshalGraph("root", g)
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return json.MarshalIndent(dg, "", " ")
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}
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// SetDebugWriter sets the io.Writer where the Graph will record debug
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// information. After this is set, the graph will immediately encode itself to
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// the stream, and continue to record all subsequent operations.
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func (g *Graph) SetDebugWriter(w io.Writer) {
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g.debug = &encoder{w: w}
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g.debug.Encode(newMarshalGraph("root", g))
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}
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// DebugVertexInfo encodes arbitrary information about a vertex in the graph
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// debug logs.
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func (g *Graph) DebugVertexInfo(v Vertex, info string) {
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va := newVertexInfo(typeVertexInfo, v, info)
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g.debug.Encode(va)
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}
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// DebugEdgeInfo encodes arbitrary information about an edge in the graph debug
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// logs.
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func (g *Graph) DebugEdgeInfo(e Edge, info string) {
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ea := newEdgeInfo(typeEdgeInfo, e, info)
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g.debug.Encode(ea)
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}
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// DebugVisitInfo records a visit to a Vertex during a walk operation.
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func (g *Graph) DebugVisitInfo(v Vertex, info string) {
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vi := newVertexInfo(typeVisitInfo, v, info)
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g.debug.Encode(vi)
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}
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// DebugOperation marks the start of a set of graph transformations in
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// the debug log, and returns a DebugOperationEnd func, which marks the end of
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// the operation in the log. Additional information can be added to the log via
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// the info parameter.
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//
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// The returned func's End method allows this method to be called from a single
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// defer statement:
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// defer g.DebugOperationBegin("OpName", "operating").End("")
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//
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// The returned function must be called to properly close the logical operation
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// in the logs.
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func (g *Graph) DebugOperation(operation string, info string) DebugOperationEnd {
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return g.debug.BeginOperation(operation, info)
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}
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// VertexName returns the name of a vertex.
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func VertexName(raw Vertex) string {
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switch v := raw.(type) {
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case NamedVertex:
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return v.Name()
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case fmt.Stringer:
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return fmt.Sprintf("%s", v)
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default:
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return fmt.Sprintf("%v", v)
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}
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}
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